/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.hadoop.hbase.util;

import java.io.IOException;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.List;

import org.apache.yetus.audience.InterfaceAudience;
//import org.apache.hadoop.hbase.shaded.protobuf.generated.ErrorHandlingProtos.Object;
//import org.apache.hadoop.hbase.shaded.protobuf.generated.ErrorHandlingProtos.GenericExceptionMessage;
//import org.apache.hadoop.hbase.shaded.protobuf.generated.ErrorHandlingProtos.StackTraceElementMessage;

/**
 * Helper to convert Exceptions and StackTraces from/to protobuf.
 * (see ErrorHandling.proto for the internal of the proto messages)
 */
@InterfaceAudience.Private
public final class ForeignExceptionUtil {
  private ForeignExceptionUtil() { }

  public static Exception toException(final Object eem) {
    Exception re;
    try {
      re = createException(Exception.class, eem);
    } catch (Throwable e) {
//      re = new Exception(eem.getGenericException().getMessage());
    }
    return setExceptionDetails(re, eem);
  }

  public static IOException toIOException(final Object eem) {
    IOException re;
    try {
      re = createException(IOException.class, eem);
    } catch (Throwable e) {
//      re = new IOException(eem.getGenericException().getMessage());
    }
    return setExceptionDetails(re, eem);
  }

  private static <T extends Exception> T createException(final Class<T> clazz,
                                                         final Object eem) throws ClassNotFoundException, NoSuchMethodException,
    InstantiationException, IllegalAccessException, InvocationTargetException {
    final Object gem = null; //eem.getGenericException();
    final Class<?> realClass = Class.forName(null);
    final Class<? extends T> cls = realClass.asSubclass(clazz);
    final Constructor<? extends T> cn = cls.getConstructor(String.class);
    cn.setAccessible(true);
    return cn.newInstance(null);
  }

  private static <T extends Exception> T setExceptionDetails(final T exception,
                                                             final Object eem) {
//    final GenericExceptionMessage gem = eem.getGenericException();
//    final StackTraceElement[] trace = toStackTrace(gem.getTraceList());
//    exception.setStackTrace(trace);
//    return exception;
    return null;
  }

  public static Object toProtoForeignException(final Throwable t) {
    return toProtoForeignException(null, t);
  }

  public static Object toProtoForeignException(String source, Throwable t) {
//    GenericExceptionMessage.Builder gemBuilder = GenericExceptionMessage.newBuilder();
//    gemBuilder.setClassName(t.getClass().getName());
//    if (t.getMessage() != null) {
//      gemBuilder.setMessage(t.getMessage());
//    }
//    // set the stack trace, if there is one
//    List<StackTraceElementMessage> stack = toProtoStackTraceElement(t.getStackTrace());
//    if (stack != null) {
//      gemBuilder.addAllTrace(stack);
//    }
//    GenericExceptionMessage payload = gemBuilder.build();
//    Object.Builder exception = Object.newBuilder();
//    exception.setGenericException(payload);
//    if (source != null) {
//      exception.setSource(source);
//    }
//
//    return exception.build();
    return null;
  }

  /**
   * Convert a stack trace to list of {@link StackTraceElement}.
   * @param trace the stack trace to convert to protobuf message
   * @return <tt>null</tt> if the passed stack is <tt>null</tt>.
   */
  public static List<Object> toProtoStackTraceElement(StackTraceElement[] trace) {
    // if there is no stack trace, ignore it and just return the message
//    if (trace == null) {
//      return null;
//    }
//
//    // build the stack trace for the message
//    List<StackTraceElementMessage> pbTrace = new ArrayList<>(trace.length);
//    for (StackTraceElement elem : trace) {
//      StackTraceElementMessage.Builder stackBuilder = StackTraceElementMessage.newBuilder();
//      stackBuilder.setDeclaringClass(elem.getClassName());
//      if (elem.getFileName() != null) {
//        stackBuilder.setFileName(elem.getFileName());
//      }
//      stackBuilder.setLineNumber(elem.getLineNumber());
//      stackBuilder.setMethodName(elem.getMethodName());
//      pbTrace.add(stackBuilder.build());
//    }
//    return pbTrace;
    return null;
  }

  /**
   * Unwind a serialized array of {@link StackTraceElementMessage}s to a
   * {@link StackTraceElement}s.
   * @param traceList list that was serialized
   * @return the deserialized list or <tt>null</tt> if it couldn't be unwound (e.g. wasn't set on
   *         the sender).
   */
  public static StackTraceElement[] toStackTrace(List<StackTraceElementMessage> traceList) {
//    if (traceList == null || traceList.isEmpty()) {
//      return new StackTraceElement[0]; // empty array
//    }
//    StackTraceElement[] trace = new StackTraceElement[traceList.size()];
//    for (int i = 0; i < traceList.size(); i++) {
//      StackTraceElementMessage elem = traceList.get(i);
//      trace[i] = new StackTraceElement(
//        elem.getDeclaringClass(), elem.getMethodName(),
//        elem.hasFileName() ? elem.getFileName() : null,
//        elem.getLineNumber());
//    }
//    return trace;
    return null;
  }
}
